[Ether]

Originally Posted by Ether

Plot this function with given values of Vo, d, and h vs x=0 to pi/3 radians.

Where it crosses the X axis is the angle solution in radians.

Vo = given initial (launch) speed feet/sec

d = horizontal distance from launch point to goal, feet

h = vertical height from launch point to goal, feet

Here's a detailed explanation of the derivation of the function.